In optical coherence tomography (OCT), to generate an image of the structure of a sample (e.g., a biological tissue), electromagnetic radiation is directed by the OCT system at the sample. Variations in the radiation that is reflected from the sample indicate structure in the sample. Ideally, to reduce artifacts in OCT images of the sample, the electromagnetic radiation directed at the sample by the OCT system should have a flat structure, without periodic variations in intensity. That is, ideally the magnitude of the electromagnetic radiation directed at the sample should not vary with wavelength. However, the OCT system can generate periodic variations in the intensity of the electromagnetic radiation, reducing image quality and introducing artifacts into OCT images.
In OCT, electromagnetic radiation is split, using an interferometer, into a reference path and an imaging path. The electromagnetic radiation returning from the reference path and imaging path are combined in the interferometer into a response signal. In OCT, structure (e.g., tissue layer contrast) is indicated by frequency variation of the response signal. However, the OCT system itself may introduce frequency components into the response signal. The frequency components introduced into the response signal may be incorrectly interpreted as structure (e.g., tissue layers) of the sample.